Throughout the history of using ionizing radiation (IR) for processing products, many variations of delivering ionizing radiation dose to the products have been developed and improved with respect to efficiency in the delivery of ionizing radiation, regardless of the means of producing the ionizing radiation. The impetus to improve this efficiency is driven by the high cost of generating IR and by the demand for higher rates of processing.
Delivery of a minimum ionizing radiation dose is required to ensure efficacy of the irradiation process. The ability to maintain the ionizing radiation dose below a maximum value is also generally required to avoid damage to the processed product or to remain below a prescribed regulatory maximum ionizing radiation dose. The ratio of maximum ionizing radiation dose to minimum ionizing radiation dose is referred to as the dose uniformity ratio (DUR). DUR and overall efficiency are closely related although efficiency also depends on aspects of delivery to the surfaces of materials being processed. Ideally, the DUR would be equal to 1.0; larger values indicate some waste of ionizing radiation.
Improvements in systems and methods for irradiating products are desirable.